The present invention relates to a signal processing device and a method for providing an oscillating signal in the signal processing device, and more particularly to a signal processing device that uses fewer oscillators, and a related method.
In a mobile system, a baseband chip can be utilized for performing various kinds of baseband coding/decoding operations, such as audio or video signal processing. In such a system, a precise clock signal should be given to the baseband chip to generate reference clock signals for the functional circuit blocks in the baseband chip. More specifically, an analog RTC (Real-time-clock) block is capable of receiving the precise clock signal, and generating the reference clock signals for the functional circuit blocks in the baseband chip. Conventionally, the precise clock signal is generated by a crystal oscillator external to the baseband chip and the analog RTC block as the crystal oscillator has a relatively stable electrical characteristic. The price of the crystal oscillator can be a problem when dealing with the BOM (Bill of Materials) cost of the mobile system, however. Therefore, how to generate a reference clock signal for the baseband chip while saving the cost of the mobile system has become a problem in this field.